SimpleEvents.js

class CustomEventSystem {
    constructor(target) {
        this.target = target;
    }
    
    trigger(event, data){
        const relay = new CustomEvent(event, { detail: (data ? data : false) });
        this.target.dispatchEvent(relay);
    }

    listen(event, listener){
        this.target.addEventListener(event, listener);
    }
}


/* Now we use it */
evSystem = new CustomEventSystem(document.querySelector('.my-element'));

evSystem.listen("hello", () => {
    console.log("Hey there");
});

evSystem.trigger("hello");